Symposium on processing and properties of polycarbonate, and on dimensional change of films whose bases are made by dope method, that which is caused by evaporation of residual solvent in the film bases, and on dimensional change of films whose bases are made from dimensionally stable synthatic resins, that which caused by the action of coated emulsion.

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In this paper, following experimental results are reported:(1) Though electron beam exposures are carried out in vacuum, shapes of the high intensity reciprocity failure curves in the reversal region for these exposures are similar to that for gamma-ray exposures in air, and (2) When film strips are exposed to gamma-rays after bathing in NaNO₂ or CH₃-COOH aq., the reciprocity failure curves shift to the high exposure side along the exposure time constant axis.

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This paper discusses methods of producing the infrared polarizer.
Ordinary visual polarizers are effective from the deep violet to just beyond the red end of the visible spectrum, but don't extend this spectral region into the infrared.
In 1950, R.P.Blake invented the process of making infrared polarizer. The steps.comprise treating a sheet of polyvinyl alcohol with a solution comprising iodine until a substantial amount of iodine approximating 35% by weight of polyvinyl alcohol is incorporated with said sheet, stretching said sheet to orient the molecules thereof, and heating said sheet for a short time between about 220°C and 230°C.
It appears that heating must result in some arrangement of the molecular structure of the iodine and sheet, probably either a lengthening of the iodine polymer chains, a stronger interaction between said polymer chains and the hydroxyl groups of the polyvinyl alcohol sheet, or both.
In the last step, we often experience that the stretched sheet is tore owing to heating at high temperature.
To prevent above defects and produce better infrared polarizer, some steps have been added by us on the process of making visual polarizer, which comprise treating a sheet of polyvinyl alcohol with a formal solution and heating said sheet at low temperature i. e. about 120°C.
The spectral characteristics of infrared polarizer prepared in accordance with the above method show high transmittance and polarizibility extending from visible to infrared region.

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The inhibiting action of several stabilisers to the production of Ag₂S by thiourea was studied. They were 5-methyl-7-oxy-1, 2, 3, 4, 6-pentazaindene, benztriazole, 6-nitrobenzimidazole, 4-ethoxy-6-methyl-1, 3, 3a, 7-tetrazaindene, and bromotriazole. AgBr containingno gelatin was ripened with thiourea in buffer, and produced Ag₂S was analised. When stabiliser was added on the halfway of the ripening, the amounts of produced Ag₂S in the subsequent process were influenced. The experimental process were following. After ripening, unreacted AgBr dissolved by sodium thiosulfate solution was separated off from formed Ag₂S by filtration. Ag₂S thus obtained was then converted to AgNO₃ by treatment with conc.HNO₃. This silver ion estimated by electrometrical titration may be considered the measure of the inhibiting action of stabiliser. The results were following, 5-methyl-7-oxy-1, 2, 3, 4, 6-pentazaindene and benztriazole had distinct inhibiting actions, others a few or not. Comparing with the data of stabilizers to emulsions and the data of this experiments, it recognized that there are fundamental differences between reaction mechanism of pentazaindene and that of benztriazole. To stop second ripening of emulsion by stabilizer, it needs to inhibit of Ag₂S in the subsequent process.

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In general, the sensitivity of photographic material is described as-log E for given density. In this paper, the authours were thought that the spectral sensitivity is the ratio of energies of totaly received on emulsion and of using for blackening effectively.
Relative spectral sensitivity of some commercial films were measured by using Konigelatine filter series of No.801-820. Calculations of experimetal results were made by using equation 1-4, and results were shown in Fig. 2. In order to ascertain these results, another experiments were carried on the some samples, and well agreed results were obtained. On the other hand, it was observed that above results in Fig. 2 were showed some differences from the spectrosensitometric results. Thus, the maximum of sensitivity in the longer wave length side than 600mμ was observed with the spectrosensitometer, but not observed in this experiments. Furthermore, it was observed that the sensitivity of the colour sensitized region of dyes were always lower than the intrinsic sensitivity region of emulsions.

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As a color film is very sensitive to ultraviolet light, to which human eyes have no sensibility, and as any of daylight and artificial light contains ultraviolet light too, use of a filter absorbing light being shorter than 410nm is very suitable for any color film, and the filter gives especially good results to take photograph of greenish or yellowish objects.

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